The present invention is directed towards a gemstone cut. Specifically, the present invention is directed towards a mixed cut gemstone with a brilliant cut crown, a girdle and a step cut pavilion. The crown in the present invention contains a flat table and a number of corner and upper girdle facets. The pavilion contains four rib lines subdividing the pavilion into four parts.
There are a variety of step, brilliant and mixed cut gemstone cuts, however, there are several problems that the prior art presents and furthermore the prior art does not address the particular need for the better gemstone cut that has superior combination of factors for scintillation, dispersion, and brilliancy. There is a long felt but unfulfilled need for a better gemstone cut that achieves best possible results for brilliancy, dispersion and scintillation.
There are several U.S. and foreign patents available, however, all of them present certain problems and do not fulfill the need for a better gemstone cut.
U.S. Pat. No. 5,970,744 to Greeff discloses a mixed cut gemstone having step cut crown with two steps and a flat table, a girdle and a pavilion. The crown and the pavilion are substantially square in shape and corners being a third of a side length. The pavilion sides and corners have rib lines that extend from the girdle to the gemstone""s culet. Each pavilion side has four facets divided. The gemstone is a combination of a step cut crown and a brilliant cut pavilion. The present invention is substantially different from this prior art. The present invention has a brilliant cut crown and a step cut pavilion. The prior art contains steps in its table, whereas the present invention has a brilliant cut crown without any steps. The pavilion of the prior art is brilliant cut without any steps, whereas the present invention contains a step cut pavilion with several steps. The features of the present invention allow it to achieve superiority over the prior art in terms of physical characteristics of a cut gemstone, such as scintillation, dispersion and brilliancy.
U.S. Pat. No. 4,020,649 to Grossbard discloses step cut stone with polygonal shaped girdle and a pyramidal base. The crown contains at least table and girdle breaks, where some of the breaks contain triangular shaped facets. The present invention contains a step cut pavilion and a brilliant cut crown. Moreover, the present invention contains greater number of steps in its pavilion, rather than this particular prior art.
U.S. Pat. No. Des. 251,659 to Grossbard disclose a mixed cut diamond having a step cut crown with a flat table, a brilliant cut pavilion having a multitude of facets with rib lines dividing sides and corners and a point culet, unlike the present invention which has a line culet. Each corner and side contains at least four facets, including lower girdle facets and bezel stars. The present invention is a mixed cut gemstone with brilliant cut crown and a step cut pavilion. The present invention""s crown does not contain any steps and its pavilion does not contain a bezel star, as in the case of this prior art.
U.S. Pat. No. Des. 391,518 to Slowinski et al. discloses a mixed cut gemstone with a square shaped crown having a polygon shaped table, table and girdle breaks with multiple facets (including upper girdle facets, bezel star facets and lower table side facets). The gemstone has brilliant cut pavilion with rib lines running from the girdle to the culet point. The sides of the pavilion have several facets, including lower girdle facets and bezel star facets. The present invention has a brilliant cut crown and a step cut pavilion, which significantly differs from the prior art.
Russian Patent No. SU 1743563-A1 discloses a mixed cut diamond with trapezoidal shaped faces on both the crown and the pavilion. The rib lines subdividing faces on the pavilion run from the girdle to the culet line. The present invention substantially differs because of having a step cut pavilion with several steps and a brilliantized crown.
While the prior art is of significant interest, it does not address a specific need of a particular way to have a mixed gemstone cut, that would achieve best possible coefficients for brilliancy, dispersion and scintillation. The present invention achieves that need by providing a mixed cut gemstone with brilliant cut crown and a step cut pavilion that has superior coefficients of brilliancy, dispersion and scintillation.
The present invention is directed toward a gemstone cut.
The main object of the present invention is to create a mixed cut gemstone with a brilliant cut crown and a step cut pavilion.
It is another object of the present invention to create a mixed cut gemstone having a brilliant cut crown, which provides for a good dispersion and scintillation.
It is another object of the present invention to create a mixed cut gemstone with a step cut pavilion.
It is another object of the present invention to create a mixed cut gemstone having a brilliant cut crown and a step cut pavilion having superior coefficients of dispersion and scintillation.
It is another object of the present invention to create a mixed cut gemstone having a limited number of faces in its crown yet achieving best results for dispersion, scintillation and brilliancy.
It is another object of the present invention to create a mixed cut gemstone with a crown having a flat table, four corner facets and four upper girdle facets.
It is another object of the present invention to create a mixed cut gemstone with multiple step cut pavilion having a point culet.
It is another object of the present invention to create a mixed cut gemstone with multiple step cut pavilion having a line culet.
It is another object of the present invention to create a mixed cut gemstone with a rectangular shaped girdle that provides for superior coefficients of dispersion, scintillation and brilliancy.
It is another object of the present invention to create a mixed cut gemstone with a square shaped girdle that provides for superior coefficients of dispersion, scintillation and brilliancy.
It is another object of the present invention to create a mixed cut gemstone with a diamond shaped table that provides for the best results in dispersion and brilliancy.
It is another object of the present invention to create a mixed cut gemstone with a diamond shaped table that is slightly elevated from the girdle plane.
It is another object of the present invention to create a mixed cut gemstone with its pavilion having four rib lines that divide the pavilion into four parts.
It is another object of the present invention to create a mixed cut gemstone with a rectangular shaped girdle where girdle length is about twice the girdle width.
Other objects will become apparent from the foregoing description.